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Cold start tuning for STi V4 plugin G4

Michael Richards

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Can anyone comment on how close the basemap is for the plugin G4 on an STi V4 vehicle? I've installed it on my own vehicle and although it starts reasonably well on the first crank the vehicle has been flooding itself after a few cold starts.


I haven't had much time to tune the vehicle yet but I did drop the master fuel value down enough to get a nice stoich idle. Are the cold-start values generally bang on already or does the map really need work? I'm just trying to determine if I should restrict my changes to the fuel injector settings, injector latency and such? The engine is close to stock with only a slightly higher compression ratio which really shouldn't affect startup that much.

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Standalone ECUs with good basemaps are derived from the factory settings so a good cold start and idle can be achieved out of the box. Fuel and timing are normally more conservative at power settings for obvious reasons. While I don't mind doing a complete tune I would prefer not to mess with things if the settings are already correct and the coldstart fuel is being hampered only by incorrect injector latency or size. Can you explain how the basemap settings were derived?

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  • 2 weeks later...

The base maps vary, for example the V7 Subaru one is very good as it was developed on our own test car over a very long time. However some of the others were very quickly done just to prove all functions and the car ran at idle.

The rule is to leave all the cold start corrections until the engine has had a full tune. And then adjust if needed.

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